Recording materials that utilize color formation resulted by reaction of a color-forming compound and a color-developing agent makes it possible to carryout recording in a short time with a relatively simple device without conducting cumbersome treatments such as developing/fixing. Such recording materials are thus widely used for thermal recording papers used for output recording such as for a facsimile and a printer, as well as for pressure sensitive copying papers used for simultaneous copying multiplicate sheets. As for these recording materials, those are desired wherein color is formed swiftly, whiteness of the no color-forming part (hereinafter referred to as “background”) is preserved, and toughness of the color-formed image and the background is high. Further, recording materials have recently been used in large quantities in the areas such as labels where credibility of the recorded images weigh heavily, and those recording materials have been strongly desired that provide color-formed images with superior storage stability against a plasticizer, fats, etc. contained in the organic high-molecular materials used for packaging. Under such circumstances, it has been studied from various aspects to solve the problems associated with not only color-forming compounds and color-developing agents but also development of various adjuvants such as storage stabilizers and the like. However, sufficiently satisfactory solutions have not yet been found.
As a compound similar to that of the present invention, there is a recording material using such as a diphenylsulfone derivative represented by formula (I).
Such recording material, however, was not yet satisfactory in respect of the image storage stability, etc. (Patent Document 1).
On the other hand, a molecular compound for use in the present invention is described in Patent Document 2, while its use as a recording material is not described therein. Therefore, value of that molecular compound as a recording material has been left unknown.    [Patent Document 1] Japanese Laid-Open Patent Application No. 8-333329    [Patent Document 2] Japanese Patent No. 3936775